Reading many of the comments people confuse memory wit visualisation. I can remember quite accurately the house I lived in as a teenager, and could draw a detailed plan of it, but that is from memory, I cannot see a picture of it in my mind at all. This does explain why I have difficulty describing faces as I cannot visualise the image, I can only remember specific features, and I would have to have seen the person for a while for the memory to set in my brain.
I have never hough that I was any different, until now, Mrs P can visualise well and our daughter even better, she cannot comprehend not being able to see a mental image. (I did a couple of tests and scored zilch.)